(Q14) To find the equation when given the gradient and one set of points (or coordinates), you have to solve for <em>b. </em> 1. Identify the gradient and x- and y- intercepts. m=3, x=1, y=5 2. Substitute them into the equation, y=mx+b. 5=3(1) + b 3. Solve for <em>b.</em> 5=3 + b b=2 4. Rewrite the equation. y=3x+ 2 (Q15) To find the equation when given two sets of points, you need to. 1. Find the gradient, using the formula, (x2-x1 / y2-y1) (7,5) and (4, -7) x1=7, x2= 4, y1=5, y2=-7 4-7/-7-5 = -3/-12 = 1/4 Therefore, gradient = 1/4 2. Substitute with one set of points (can be either (7,5) or (4,-7) in this example - question 15) into the equation, (like you did in question 14) a) Identify the gradient and x- and y- intercepts. m=1/4, x=7, y=5 b) Solve for <em>b</em>. 5=1/4(7) + <em></em>b 5=7/4 + b b=13/4 or 3 1/4 c) Rewrite the equation. y=1/4x + 13/4
